In typical commercial reproduction apparatus (electrographic copier/duplicators, printers, or the like), a latent image charge pattern is formed on a uniformly charged charge-retentive or photoconductive member having dielectric characteristics (hereinafter referred to as the dielectric support member). Pigmented marking particles are attracted to the latent image charge pattern to develop such image on the dielectric support member. A receiver member, such as a sheet of paper, transparency or other medium, is then brought directly, or indirectly via an intermediate transfer member, into contact with the dielectric support member, and an electric field is applied to transfer the marking particle developed image to the receiver member from the dielectric support member. After transfer, the receiver member bearing the transferred image is transported away from the dielectric support member, and the image is fixed (fused) to the receiver member by heat and/or pressure to form a permanent reproduction thereon.
One type of development station commonly utilized in electrographic reproduction apparatus is the magnetic brush development station, such as shown in U.S. Pat. No. 6,385,415, issued on May 7, 2002, in the names of Hilbert et al. The magnetic brush development station includes a housing providing a reservoir for a supply of developer material. The developer material may be, for example, two-component material including magnetic carrier particles and relatively smaller pigmented marking particles. A mechanism, such as a paddle wheel, auger, or ribbon blender, is located in the reservoir and serves to stir the carrier particles and marking particles to triboelectrically charge the particles so that the marking particles adhere to the surface of the carrier particles. A transport mechanism brings the developer material into the field of a plurality of magnets within a sleeve (commonly referred to as a developer or toning roller). The plurality of magnets and the sleeve are caused to rotate relative to one another such that the magnetic field of the magnets causes the marking particles to be brought into the vicinity of the latent image charge patterns on the dielectric support member. The marking particles are thus applied to the latent image charge patterns in order to adhere to, and thereby develop such patterns.
While magnetic brush development stations of the above-described type are generally suitable for operation in present commercial reproduction apparatus, improvements in speed and range of use escalate the demands on all of the systems of the reproduction apparatus, especially the development station. For example, reliability of the magnetic brush developer station can be affected when marking particles contaminate drive components, seals, and circuit boards. Increased customer and/or service personnel time to clean these components reduces the available up-time and productivity of the equipment. Contaminates are especially disturbing to the magnetic brush developer station performance at the point where developer material is metered onto the developer roller. Metering is necessary to provide a layer of developer material of only that thickness which will serve to optimally develop the image charge pattern on the dielectric support member. Any developer material flow disturbances lead to image quality artifacts in the finished permanent reproduction. Contaminants tend to collect on the metering skive, particularly when the contaminants are larger than the skive spacing from the developer roller. Collected contaminants then impede uniform flow of developer material to the developing zone into association with the dielectric support member, and generate the noted artifacts by, for example, causing incomplete image development. It is therefore desirable to prevent build up of contaminates at the metering skive.